PhD fellowship: Control of the human kinome and autophagy by the docking of 14-3-3 proteins onto phosphoproteins

Professor Carol MacKintosh, School of Life Sciences, University of Dundee, Scotland, UK.

Application Deadline 30 April 2017

Start date 4 September 2017

Applicants must be starting researchers and conform to the Eligibility and Mobility Rules for Marie Curie Initial Training Networks.

Project Description

14-3-3 proteins are major participants in the intracellular signalling networks that transduce information from the extracellular environment to coordinate changes in protein activity and gene expression. The 14-3-3s are dimeric and dock onto specific pairs of phosphosites in thousands of target proteins. These paired sites sometimes straddle a domain or motif whose function is masked by the 14-3-3. In other cases, 14-3-3 binding to two phosphosites in a disordered region forces a disorder-to-order transition that creates a new functional site in the target protein.

The MacKintosh lab has discovered that, remarkably, most human 14-3-3–binding phosphoproteins are 2R-ohnologues, which are proteins encoded by gene families that were generated by an evolutionary leap involving two rounds of whole genome duplication (2R-WGD) at the origin of the vertebrates. Via the 2R-WGD, the ancestral linear signalling pathways were quadrupled and evolved into signalling networks, and these networks are enriched in 14-3-3-binding phosphoproteins.

Within these vertebrate signalling networks, we often find that one 2R-ohnologue protein is phosphorylated and binds to 14-3-3 in response to insulin (for example), while its sisters are phosphorylated and bind to 14-3-3 in response to growth factors or cAMP-elevating agents. We believe that this ‘pick-and-mix’ model helps explain how vertebrate cells can tune into a wide array of sensory and hormonal stimuli and integrate them to generate different phenotypic responses. Thus, the 14-3-3-binding phosphoproteome is fundamental to the evolution of complexity and variety in vertebrate life. Moreover, we find that cancer mutations rewire the 14-3-3-regulated signalling networks in specific patterns that are shared by multiple cancers.

In close collaboration with the Ganley lab, University of Dundee, this project will elucidate how the sets of sister 2R-ohnologues that regulate autophagy are controlled by phosphorylation and 14-3-3 proteins. In autophagy (from the Greek ‘to eat oneself’), unwanted cellular components are engulfed by a specialised structure known as the autophagosome and delivered to the digestive lysosome for degradation. This essential process prevents the cell from ending up a rubbish dump, and because of this, impaired autophagy has been linked to many diseases, including cancers. The specific targets to be studied include the protein kinases ULK1 and ULK2 that signal to activate autophagy when cells are deprived of nutrients, and ATG9A and ATG9B, transmembrane proteins that help organise autophagosome structures. The project will also investigate how autophagy is influenced by small-molecules that disrupt or stabilise 14-3-3–phosphoprotein interactions, and will use cell-based biochemical approaches, phosphoproteomics and state-of-the-art microscopy.

Funding Notes

We offer a 3-year Innovative Training Network studentship, which is funded as part of the http://www.tasppi.eu/ project. The position carries a salary of £27,328 to £34,576 per annum in accordance with the EU financial guidelines for this scheme until February 2020, after which there will be a stipend at RCUK rates until September 2020.

To apply, applicants must:

have spent less than 4 years on full-time research at the time of their recruitment